Set aside 1 tablespoon of wafer crumbs for garnish. In a bowl, combine the sugar and remaining crumbs. Stir in butter. Press onto the bottom and up the sides of greased 9-in. pie plate. Refrigerate for 1 hour or until set.
In a bowl, combine ice cream and peanut butter. Fold in whipped topping. Pour into pie shell. Top with reserved crumbs and peanuts if desired. Cover and freeze for at least 2 hours. Remove from the freezer 15 minutes before cutting.